Rust CLI POC — Python BDD Integration

This repository is a proof of concept demonstrating how a Rust-based command-line interface (CLI) can be controlled and tested using Python, Behave, and BDD-style Gherkin scenarios. The goal is to show how UI actions (e.g., "press play", "turn knob") can be expressed as natural-language tests, executed via Python, and mapped to real commands inside a Rust application.

Overview

This project contains:

1. A minimal Rust CLI

Located in src/main.rs, the CLI accepts simple commands such as:

• play
• stop
• tempo

Example:

./target/debug/rust_cli_poc play

Output:

Sequencer started.

This simulates a hardware/UI interaction through a CLI interface.

Python Behave Test (BDD)

Inside the features/ directory you'll find:

• Gherkin feature file (sequencer.feature)
• Step definitions (steps.sequencer_steps.py)

A Sample scenerio:

  Scenario: Starting the sequencer
    When I press play
    Then I see the sequencer start

Behave maps these steps to Python functions that execute the Rust CLI using subprocess.run() and verify the outputs.

Goal of the POC

This proof-of-concept shows how the project could:

• Use BDD for acceptance tests.
• Connect Python test steps to real Rust binary behavior.
• Simulate UI elements (buttons, knobs) through CLI commands.
• Provide a foundation for automated hardware/UI regression testing.
• Give non-Rust developers a natural-language interface for describing behavior.

Setup & Usage

1. Build the Rust CLI cargo build
2. Run the CLI manually ./target/debug/rust_cli_poc play
3. Install Poetry dependencies

curl -sSL https://install.python-poetry.org | python3 -

Then run:

poetry install

4. Run the Behave BDD tests

behave

Why This Approach?

• Using Python Behave + Rust CLI provides:
• A human-friendly BDD layer ("When I press play…")
• A clear interface between UI behavior and CLI commands
• Fast and portable tests
• Easy extension to hardware or embedded interfaces
• Team-friendly documentation for expected behavior
• This is a lightweight but powerful workflow to validate user interactions, end-to-end system behavior, or automated UI tests.